In the related art, when an optical element is used in an optical instrument, an optical assembly in which a plurality of the optical elements are combined and the relative positions thereof are fixed is used. As an example of such an optical assembly, for example, an optical unit in which a plurality of lenses are fixed to a holding frame can be mentioned.
In recent years, an improvement in performance of the optical instrument has been required, and the required quality of the optical properties of the optical assembly is also made high with this improvement.
In order to improve the optical performance of the optical assembly, it is necessary to improve the part precision of the respective optical elements or the holding frame included in the optical assembly. However, if only part precision is considered in order to achieve the required quality, there is a problem in that a processing limit is reached, or production costs are excessively increased even if processing is possible.
For this reason, for example, the optical elements or the holding frame may be stratified with shape errors and combined or assembled so that assembly errors are reduced, or the optical elements may be adjusted in positions and assembled at positions where the optical properties becomes excellent while evaluating the optical properties.
For example, in Japanese Unexamined Patent Application, First Publication No. 2010-243961, a technique is described of assembling respective lenses to a lens barrel using a lens spacing-adjusting method for bonding and fixing two lenses to the lens barrel in a state where the lenses are temporarily supported by a spacer jig, and then extracting the spacer jig.